Multi-flue type commercial water heaters have historically provided two serious problems. These heaters are prone to temperature stacking of the stored water with the water in the top of the heater tank being overheated. And because of the firing of the bottom head of the tank from outside, these commercial water heaters are highly subject to early failure because of sediment deposit on the bottom head. The invention overcomes these problems by a specially constructed cold water inlet tube which improves draw and reduces both stacking of the stored water and sediment deposits.